1. Field of the Invention
The present invention is related to a computer system and particularly to a computer system having main boards which can be controlled independently.
2. Description of Related Art
FIG. 1 is a circuit block diagram of a conventional computer system. Referring to FIG. 1, a conventional computer system 100 includes a plurality of main boards 110-130 and a power supply 140. In overall operation, the main boards 110-130 determine whether to output power start signals PSON_11, PSON_12 and PSON_13 according to received identification codes.
On the other hand, for the power supply 140, when the power start signals PSON_11, PSON_12 or PSON_13 is received, the power supply 140 outputs an operating voltage PW1 and a power reply signal PSOK1. Thus, when the main boards 110-130 receive the power reply signal PSOK1, the main boards 110-130 detect that the power supply 140 has started providing power. At this moment, the main boards 110-130 use the operating voltage PW1 to drive inner circuits thereof and start acting.
It should be noted that the power start signals PSON_11, PSON_12 and PSON_13 are transmitted to the power supply 140 through the same line, and the power supply 140 transmits simultaneously the operating voltage PW1 and the power reply signal PSOK1 to each of the main boards 110-130. Therefore, when only the main board 110 outputs the power start signal PSON_11 and the remaining main boards 120-130 do not output the power start signals PSON_12 and PSON_13, the main boards 110-130 are all driven by the power supply 140 to operate at the operating voltage PW1.
In other words, for the conventional computer system 100, the main boards 110-130 cannot act independently. Such circumstances not only cause inconvenience to users during operation, but also cause the conventional computer system 100 to consume more power.